For geeks, it's an opportunity to get our hands on all the stuff Microsoft has been showing off, in trickle-out fashion, since January 2011.

But if you don't follow the ups and downs of technology closely, it can seem awfully confusing. Is it for tablets or not? Is it an iPad killer, or just another update to the same old Windows we've been using for the last 15 years?

All of the above. Sort of.

Here's what you need to know, laid out in FAQ form.

Q: Who cares about Windows? Everybody has a smartphone or iPad these days.

But Windows is still the most popular operating system in the world. People still bought more than 350 million PCs last year -- mostly notebooks and some desktops. They're still standard issue in most businesses. Most run Windows.

And Microsoft and its investors still care a lot about Windows: it's the company's single biggest-selling and most profitable product, earning $12 billion in profit on almost $19 billion in sales over the last four quarters. It's also the cornerstone of Microsoft's other businesses. If Windows fails, Microsoft fails.

Q. So what's the most important new thing in Windows 8?

A. Windows 8 will have a totally new design that is meant to be used with touch screens like the ones found on an iPad or Kindle Fire (or any other tablet). It looks like this:

Windows 8 in action.

That interface is nicknamed Metro, and it features bright colored squares, sliding menus, and a Windows Store that's very much like Apple's App Store.

Microsoft is careful to say that Windows 8 Metro is for touch screens -- not just tablets. The company and its hardware partners, like HP, Dell, and Sony, will probably build computers that can be "converted" from laptops into tablets, or tablets that turn into a regular computer when they're attached to a docking station.

Q. It looks kind of like those phones Microsoft and Nokia have been pushing, right?

A. Yes. The Metro look and feel first showed up on Windows Phone. The underlying technology is quite different today but eventually will be the same.

Q. Will Windows 8 work on regular computers, too?

A. Yes. This is part of what Windows chief Steven Sinofsky has called Microsoft's "no compromises" approach to Windows.

When you start a Windows 8 computer, you'll see the Metro interface. Metro was made for touch screens, but it will work well with a keyboard and mouse too, as Microsoft demonstrated today. (A video is here -- it can't be embedded.)

From within Metro, you'll be able to open an app that basically takes you back to the old Windows desktop look and feel, with the usual slight updates that come with every new version of Windows. Some applications, like Microsoft Word and Excel, will only use this desktop version of Windows.

Macs, which are designed to be used with keyboards and mice (or touchpads) use OS X, which has been around for a little more than a decade now. The iPad is based on iOS, which was introduced with the iPhone in 2007.

Apple's reasoning is that touch screen devices should work like each other, and should work differently from keyboard-mouse computers.

Microsoft would rather sell one version of Windows that works on different kinds of devices.

A Windows tablet.Ellis Hamburger, Business Insider

Q. So Windows 8 is supposed to be Microsoft's iPad killer, right?

A. Not really.

In fact, this is where the story gets really confusing.

The iPad runs on a type of processor based on a design from a British company called ARM. Most other tablets do, as well. ARM processors are more energy efficient than the processors used in most PCs, which are based on designs from Intel.

Windows 8 will run only on Intel-type processors. So unless Intel comes up with some huge advances, soon, Windows 8 tablets will probably have significantly less battery life than the iPad. That will make them a tough sell to consumers.

Businesses might still buy them so they can install old software apps on them, manage them with the same tools they use to manage regular Windows PCs, and so on.

Q. So does Microsoft even HAVE an answer to the iPad?

A. Kind of.

Windows 8 isn't the only new operating system from Microsoft. The company is also coming out with a separate product called Windows On ARM (or WOA for short). WOA will look like Windows 8, but the computers that run it will be quite different.

For instance:

These computers will only include the Metro (touch screen) interface. For the most part, you won't be able to get the traditional Windows desktop. (Microsoft's Internet Explorer and Office will automatically open in desktop mode, which will be a clunky experience, but that's probably a temporary thing until Microsoft can rewrite those apps for Metro.)

They will all have touch screens. No traditional laptop or desktop PCs.

They will not run old Windows apps -- only new apps written for Metro. No Office 2010. No current versions of Photoshop or Quicken.

You will only be able to download apps through the Windows Store. This will be just like the iPad and Apple App Store. You won't be buying disks and installing them like you do on PCs today.

The software and hardware will come together. WOA will only come preinstalled on new tablets. You won't be able to buy WOA in a store and build your own tablet, like you can with other versions of Windows. You won't be able to buy a disk with a new version of WOA and install it on your iPad (although hackers might figure out a way to do this).

Q. So there will be two very different kinds of Windows tablets. How will people know what they're buying?

A. Microsoft says it will use clear labeling and packaging so consumers know what they're getting.

This hasn't worked so well in the past -- Windows Vista had different "certifications" that would tell you whether a computer could run the full version or a crippled version called Home Basic. It was very confusing. Some customers even sued Microsoft about it. (It was basically dismissed, though.)

Our hunch is that most Windows tablets will turn out to be these WOA tablets, and that Windows 8 will probably be found mostly on regular computers and some "convertibles."

Q. W

hy would anybody buy one of these iPad killers instead of an actual Apple iPad?

A. We're not sure. They won't run traditional Windows apps. They won't work with the management tools that IT departments love.

It will basically come down to whether Microsoft can convince developers to build lots of cool apps for Metro, and convince consumers that the overall experience is better. It will also have to inspire its hardware partners to build tablets that look, feel, and work as well or better than the iPad.

Microsoft does have some advantages over Apple. Some workers will probably like having Office on their tablet (if Microsoft doesn't release it for the iPad first). Microsoft understands Internet services better than Apple -- for instance, the contact syncing on the Windows Phone (which is Microsoft's smartphone platform) is way smoother than it is on the iPhone. Developers will probably build lots of apps for them, since they can also target the hundreds of millions of regular Windows 8 PCs that will ship.

But the iPad will also be on its third revision and have an almost three-year head start.

Q. So Windows 8 could be a total flop, then.

A. Doubtful. Even if nobody buys Windows tablets in any form (Windows 8 or WOA), there will probably still be hundreds of millions of regular PCs sold in the next few years, and most of those PCs will probably come with Windows 8.

But in the long run, if nobody buys Windows tablets, that means the iPad (and possibly Android or other tablets) will take more and more market share, particularly among consumers. Windows PCs will be relegated to businesses.